Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | |
| 2 | config PRINTK_TIME |
| 3 | bool "Show timing information on printks" |
| 4 | help |
| 5 | Selecting this option causes timing information to be |
| 6 | included in printk output. This allows you to measure |
| 7 | the interval between kernel operations, including bootup |
| 8 | operations. This is useful for identifying long delays |
| 9 | in kernel startup. |
| 10 | |
| 11 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | config MAGIC_SYSRQ |
| 13 | bool "Magic SysRq key" |
Adrian Bunk | f346f4b | 2006-01-09 20:54:51 -0800 | [diff] [blame] | 14 | depends on !UML |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | help |
| 16 | If you say Y here, you will have some control over the system even |
| 17 | if the system crashes for example during kernel debugging (e.g., you |
| 18 | will be able to flush the buffer cache to disk, reboot the system |
| 19 | immediately or dump some status information). This is accomplished |
| 20 | by pressing various keys while holding SysRq (Alt+PrintScreen). It |
| 21 | also works on a serial console (on PC hardware at least), if you |
| 22 | send a BREAK and then within 5 seconds a command keypress. The |
| 23 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y |
| 24 | unless you really know what this hack does. |
| 25 | |
Arjan van de Ven | f71d20e | 2006-06-28 04:26:45 -0700 | [diff] [blame] | 26 | config UNUSED_SYMBOLS |
| 27 | bool "Enable unused/obsolete exported symbols" |
| 28 | default y if X86 |
| 29 | help |
| 30 | Unused but exported symbols make the kernel needlessly bigger. For |
| 31 | that reason most of these unused exports will soon be removed. This |
| 32 | option is provided temporarily to provide a transition period in case |
| 33 | some external kernel module needs one of these symbols anyway. If you |
| 34 | encounter such a case in your module, consider if you are actually |
| 35 | using the right API. (rationale: since nobody in the kernel is using |
| 36 | this in a module, there is a pretty good chance it's actually the |
| 37 | wrong interface to use). If you really need the symbol, please send a |
| 38 | mail to the linux kernel mailing list mentioning the symbol and why |
| 39 | you really need it, and what the merge plan to the mainline kernel for |
| 40 | your module is. |
| 41 | |
Adrian Bunk | f346f4b | 2006-01-09 20:54:51 -0800 | [diff] [blame] | 42 | config DEBUG_KERNEL |
| 43 | bool "Kernel debugging" |
| 44 | help |
| 45 | Say Y here if you are developing drivers or trying to debug and |
| 46 | identify kernel problems. |
| 47 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | config LOG_BUF_SHIFT |
| 49 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL |
| 50 | range 12 21 |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 51 | default 17 if S390 || LOCKDEP |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | default 16 if X86_NUMAQ || IA64 |
| 53 | default 15 if SMP |
| 54 | default 14 |
| 55 | help |
| 56 | Select kernel log buffer size as a power of 2. |
| 57 | Defaults and Examples: |
| 58 | 17 => 128 KB for S/390 |
| 59 | 16 => 64 KB for x86 NUMAQ or IA-64 |
| 60 | 15 => 32 KB for SMP |
| 61 | 14 => 16 KB for uniprocessor |
| 62 | 13 => 8 KB |
| 63 | 12 => 4 KB |
| 64 | |
Ingo Molnar | 8446f1d | 2005-09-06 15:16:27 -0700 | [diff] [blame] | 65 | config DETECT_SOFTLOCKUP |
| 66 | bool "Detect Soft Lockups" |
| 67 | depends on DEBUG_KERNEL |
| 68 | default y |
| 69 | help |
| 70 | Say Y here to enable the kernel to detect "soft lockups", |
| 71 | which are bugs that cause the kernel to loop in kernel |
| 72 | mode for more than 10 seconds, without giving other tasks a |
| 73 | chance to run. |
| 74 | |
| 75 | When a soft-lockup is detected, the kernel will print the |
| 76 | current stack trace (which you should report), but the |
| 77 | system will stay locked up. This feature has negligible |
| 78 | overhead. |
| 79 | |
| 80 | (Note that "hard lockups" are separate type of bugs that |
| 81 | can be detected via the NMI-watchdog, on platforms that |
| 82 | support it.) |
| 83 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | config SCHEDSTATS |
| 85 | bool "Collect scheduler statistics" |
| 86 | depends on DEBUG_KERNEL && PROC_FS |
| 87 | help |
| 88 | If you say Y here, additional code will be inserted into the |
| 89 | scheduler and related routines to collect statistics about |
| 90 | scheduler behavior and provide them in /proc/schedstat. These |
| 91 | stats may be useful for both tuning and debugging the scheduler |
| 92 | If you aren't debugging the scheduler or trying to tune a specific |
| 93 | application, you can say N to avoid the very slight overhead |
| 94 | this adds. |
| 95 | |
| 96 | config DEBUG_SLAB |
Andrew Morton | 4a2f0ac | 2006-03-25 03:07:22 -0800 | [diff] [blame] | 97 | bool "Debug slab memory allocations" |
Ingo Molnar | 50dd26ba | 2006-01-08 01:01:42 -0800 | [diff] [blame] | 98 | depends on DEBUG_KERNEL && SLAB |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | help |
| 100 | Say Y here to have the kernel do limited verification on memory |
| 101 | allocation as well as poisoning memory on free to catch use of freed |
| 102 | memory. This can make kmalloc/kfree-intensive workloads much slower. |
| 103 | |
Al Viro | 871751e | 2006-03-25 03:06:39 -0800 | [diff] [blame] | 104 | config DEBUG_SLAB_LEAK |
| 105 | bool "Memory leak debugging" |
| 106 | depends on DEBUG_SLAB |
| 107 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | config DEBUG_PREEMPT |
| 109 | bool "Debug preemptible kernel" |
Ingo Molnar | 8637c09 | 2006-07-03 00:24:38 -0700 | [diff] [blame] | 110 | depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | default y |
| 112 | help |
| 113 | If you say Y here then the kernel will use a debug variant of the |
| 114 | commonly used smp_processor_id() function and will print warnings |
| 115 | if kernel code uses it in a preemption-unsafe way. Also, the kernel |
| 116 | will detect preemption count underflows. |
| 117 | |
Ingo Molnar | e7eebaf | 2006-06-27 02:54:55 -0700 | [diff] [blame] | 118 | config DEBUG_RT_MUTEXES |
| 119 | bool "RT Mutex debugging, deadlock detection" |
Ingo Molnar | e7eebaf | 2006-06-27 02:54:55 -0700 | [diff] [blame] | 120 | depends on DEBUG_KERNEL && RT_MUTEXES |
| 121 | help |
| 122 | This allows rt mutex semantics violations and rt mutex related |
| 123 | deadlocks (lockups) to be detected and reported automatically. |
| 124 | |
| 125 | config DEBUG_PI_LIST |
| 126 | bool |
| 127 | default y |
| 128 | depends on DEBUG_RT_MUTEXES |
| 129 | |
Thomas Gleixner | 61a8712 | 2006-06-27 02:54:56 -0700 | [diff] [blame] | 130 | config RT_MUTEX_TESTER |
| 131 | bool "Built-in scriptable tester for rt-mutexes" |
Roman Zippel | a1583d3 | 2006-06-27 02:55:00 -0700 | [diff] [blame] | 132 | depends on DEBUG_KERNEL && RT_MUTEXES |
Thomas Gleixner | 61a8712 | 2006-06-27 02:54:56 -0700 | [diff] [blame] | 133 | help |
| 134 | This option enables a rt-mutex tester. |
| 135 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | config DEBUG_SPINLOCK |
Ingo Molnar | 4d9f34a | 2006-07-03 00:24:55 -0700 | [diff] [blame] | 137 | bool "Spinlock and rw-lock debugging: basic checks" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | depends on DEBUG_KERNEL |
| 139 | help |
| 140 | Say Y here and build SMP to catch missing spinlock initialization |
| 141 | and certain other kinds of spinlock errors commonly made. This is |
| 142 | best used in conjunction with the NMI watchdog so that spinlock |
| 143 | deadlocks are also debuggable. |
| 144 | |
Ingo Molnar | 4d9f34a | 2006-07-03 00:24:55 -0700 | [diff] [blame] | 145 | config DEBUG_MUTEXES |
| 146 | bool "Mutex debugging: basic checks" |
| 147 | depends on DEBUG_KERNEL |
| 148 | help |
| 149 | This feature allows mutex semantics violations to be detected and |
| 150 | reported. |
| 151 | |
| 152 | config DEBUG_RWSEMS |
| 153 | bool "RW-sem debugging: basic checks" |
| 154 | depends on DEBUG_KERNEL |
| 155 | help |
| 156 | This feature allows read-write semaphore semantics violations to |
| 157 | be detected and reported. |
| 158 | |
| 159 | config DEBUG_LOCK_ALLOC |
| 160 | bool "Lock debugging: detect incorrect freeing of live locks" |
| 161 | depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
| 162 | select DEBUG_SPINLOCK |
| 163 | select DEBUG_MUTEXES |
| 164 | select DEBUG_RWSEMS |
| 165 | select LOCKDEP |
| 166 | help |
| 167 | This feature will check whether any held lock (spinlock, rwlock, |
| 168 | mutex or rwsem) is incorrectly freed by the kernel, via any of the |
| 169 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), |
| 170 | vfree(), etc.), whether a live lock is incorrectly reinitialized via |
| 171 | spin_lock_init()/mutex_init()/etc., or whether there is any lock |
| 172 | held during task exit. |
| 173 | |
| 174 | config PROVE_LOCKING |
| 175 | bool "Lock debugging: prove locking correctness" |
| 176 | depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
| 177 | select LOCKDEP |
| 178 | select DEBUG_SPINLOCK |
| 179 | select DEBUG_MUTEXES |
| 180 | select DEBUG_RWSEMS |
| 181 | select DEBUG_LOCK_ALLOC |
| 182 | default n |
| 183 | help |
| 184 | This feature enables the kernel to prove that all locking |
| 185 | that occurs in the kernel runtime is mathematically |
| 186 | correct: that under no circumstance could an arbitrary (and |
| 187 | not yet triggered) combination of observed locking |
| 188 | sequences (on an arbitrary number of CPUs, running an |
| 189 | arbitrary number of tasks and interrupt contexts) cause a |
| 190 | deadlock. |
| 191 | |
| 192 | In short, this feature enables the kernel to report locking |
| 193 | related deadlocks before they actually occur. |
| 194 | |
| 195 | The proof does not depend on how hard and complex a |
| 196 | deadlock scenario would be to trigger: how many |
| 197 | participant CPUs, tasks and irq-contexts would be needed |
| 198 | for it to trigger. The proof also does not depend on |
| 199 | timing: if a race and a resulting deadlock is possible |
| 200 | theoretically (no matter how unlikely the race scenario |
| 201 | is), it will be proven so and will immediately be |
| 202 | reported by the kernel (once the event is observed that |
| 203 | makes the deadlock theoretically possible). |
| 204 | |
| 205 | If a deadlock is impossible (i.e. the locking rules, as |
| 206 | observed by the kernel, are mathematically correct), the |
| 207 | kernel reports nothing. |
| 208 | |
| 209 | NOTE: this feature can also be enabled for rwlocks, mutexes |
| 210 | and rwsems - in which case all dependencies between these |
| 211 | different locking variants are observed and mapped too, and |
| 212 | the proof of observed correctness is also maintained for an |
| 213 | arbitrary combination of these separate locking variants. |
| 214 | |
| 215 | For more details, see Documentation/lockdep-design.txt. |
| 216 | |
| 217 | config LOCKDEP |
| 218 | bool |
| 219 | depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
| 220 | select STACKTRACE |
| 221 | select FRAME_POINTER |
| 222 | select KALLSYMS |
| 223 | select KALLSYMS_ALL |
| 224 | |
| 225 | config DEBUG_LOCKDEP |
| 226 | bool "Lock dependency engine debugging" |
| 227 | depends on LOCKDEP |
| 228 | help |
| 229 | If you say Y here, the lock dependency engine will do |
| 230 | additional runtime checks to debug itself, at the price |
| 231 | of more runtime overhead. |
| 232 | |
| 233 | config TRACE_IRQFLAGS |
| 234 | bool |
| 235 | default y |
| 236 | depends on TRACE_IRQFLAGS_SUPPORT |
| 237 | depends on PROVE_LOCKING |
| 238 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | config DEBUG_SPINLOCK_SLEEP |
Ingo Molnar | 4d9f34a | 2006-07-03 00:24:55 -0700 | [diff] [blame] | 240 | bool "Spinlock debugging: sleep-inside-spinlock checking" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 241 | depends on DEBUG_KERNEL |
| 242 | help |
| 243 | If you say Y here, various routines which may sleep will become very |
| 244 | noisy if they are called with a spinlock held. |
| 245 | |
Ingo Molnar | cae2ed9 | 2006-07-03 00:24:48 -0700 | [diff] [blame] | 246 | config DEBUG_LOCKING_API_SELFTESTS |
| 247 | bool "Locking API boot-time self-tests" |
| 248 | depends on DEBUG_KERNEL |
| 249 | help |
| 250 | Say Y here if you want the kernel to run a short self-test during |
| 251 | bootup. The self-test checks whether common types of locking bugs |
| 252 | are detected by debugging mechanisms or not. (if you disable |
| 253 | lock debugging then those bugs wont be detected of course.) |
| 254 | The following locking APIs are covered: spinlocks, rwlocks, |
| 255 | mutexes and rwsems. |
| 256 | |
Ingo Molnar | 8637c09 | 2006-07-03 00:24:38 -0700 | [diff] [blame] | 257 | config STACKTRACE |
| 258 | bool |
| 259 | depends on STACKTRACE_SUPPORT |
| 260 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | config DEBUG_KOBJECT |
| 262 | bool "kobject debugging" |
| 263 | depends on DEBUG_KERNEL |
| 264 | help |
| 265 | If you say Y here, some extra kobject debugging messages will be sent |
| 266 | to the syslog. |
| 267 | |
| 268 | config DEBUG_HIGHMEM |
| 269 | bool "Highmem debugging" |
| 270 | depends on DEBUG_KERNEL && HIGHMEM |
| 271 | help |
| 272 | This options enables addition error checking for high memory systems. |
| 273 | Disable for production systems. |
| 274 | |
| 275 | config DEBUG_BUGVERBOSE |
| 276 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED |
Matt Mackall | c8538a7 | 2005-05-01 08:59:01 -0700 | [diff] [blame] | 277 | depends on BUG |
Brian Gerst | 0d078f6 | 2005-10-30 14:59:20 -0800 | [diff] [blame] | 278 | depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | default !EMBEDDED |
| 280 | help |
| 281 | Say Y here to make BUG() panics output the file name and line number |
| 282 | of the BUG call as well as the EIP and oops trace. This aids |
| 283 | debugging but costs about 70-100K of memory. |
| 284 | |
| 285 | config DEBUG_INFO |
| 286 | bool "Compile the kernel with debug info" |
| 287 | depends on DEBUG_KERNEL |
| 288 | help |
| 289 | If you say Y here the resulting kernel image will include |
| 290 | debugging info resulting in a larger kernel image. |
| 291 | Say Y here only if you plan to debug the kernel. |
| 292 | |
| 293 | If unsure, say N. |
| 294 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 | config DEBUG_FS |
| 296 | bool "Debug Filesystem" |
Jens Axboe | ae36b88 | 2006-03-26 14:38:54 +0200 | [diff] [blame] | 297 | depends on SYSFS |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | help |
| 299 | debugfs is a virtual file system that kernel developers use to put |
| 300 | debugging files into. Enable this option to be able to read and |
| 301 | write to these files. |
| 302 | |
| 303 | If unsure, say N. |
| 304 | |
Paul E. McKenney | a241ec6 | 2005-10-30 15:03:12 -0800 | [diff] [blame] | 305 | config DEBUG_VM |
| 306 | bool "Debug VM" |
| 307 | depends on DEBUG_KERNEL |
| 308 | help |
Nick Piggin | 13e7444 | 2006-01-06 00:10:58 -0800 | [diff] [blame] | 309 | Enable this to turn on extended checks in the virtual-memory system |
| 310 | that may impact performance. |
Paul E. McKenney | a241ec6 | 2005-10-30 15:03:12 -0800 | [diff] [blame] | 311 | |
| 312 | If unsure, say N. |
| 313 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 314 | config FRAME_POINTER |
| 315 | bool "Compile the kernel with frame pointers" |
Heiko Carstens | cbbd1fa | 2006-07-03 00:24:38 -0700 | [diff] [blame] | 316 | depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390) |
Paolo 'Blaisorblade' Giarrusso | 37fce85 | 2005-05-28 15:51:59 -0700 | [diff] [blame] | 317 | default y if DEBUG_INFO && UML |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 318 | help |
| 319 | If you say Y here the resulting kernel image will be slightly larger |
Jesper Juhl | 2a38bcc | 2005-10-30 15:02:51 -0800 | [diff] [blame] | 320 | and slower, but it might give very useful debugging information on |
| 321 | some architectures or if you use external debuggers. |
Andi Kleen | aeb3998 | 2005-09-12 18:49:25 +0200 | [diff] [blame] | 322 | If you don't debug the kernel, you can say N. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | |
Jan Beulich | 604bf5a | 2006-03-24 03:16:19 -0800 | [diff] [blame] | 324 | config UNWIND_INFO |
| 325 | bool "Compile the kernel with frame unwind information" |
Jan Beulich | 4552d5d | 2006-06-26 13:57:28 +0200 | [diff] [blame] | 326 | depends on !IA64 && !PARISC |
| 327 | depends on !MODULES || !(MIPS || PPC || SUPERH || V850) |
Jan Beulich | 604bf5a | 2006-03-24 03:16:19 -0800 | [diff] [blame] | 328 | help |
| 329 | If you say Y here the resulting kernel image will be slightly larger |
| 330 | but not slower, and it will give very useful debugging information. |
| 331 | If you don't debug the kernel, you can say N, but we may not be able |
| 332 | to solve problems without frame unwind information or frame pointers. |
| 333 | |
Jan Beulich | 4552d5d | 2006-06-26 13:57:28 +0200 | [diff] [blame] | 334 | config STACK_UNWIND |
| 335 | bool "Stack unwind support" |
| 336 | depends on UNWIND_INFO |
Jan Beulich | 176a271 | 2006-06-26 13:57:41 +0200 | [diff] [blame] | 337 | depends on X86 |
Jan Beulich | 4552d5d | 2006-06-26 13:57:28 +0200 | [diff] [blame] | 338 | help |
| 339 | This enables more precise stack traces, omitting all unrelated |
| 340 | occurrences of pointers into kernel code from the dump. |
| 341 | |
Ingo Molnar | a9df3d0 | 2006-01-14 13:21:33 -0800 | [diff] [blame] | 342 | config FORCED_INLINING |
| 343 | bool "Force gcc to inline functions marked 'inline'" |
| 344 | depends on DEBUG_KERNEL |
| 345 | default y |
| 346 | help |
| 347 | This option determines if the kernel forces gcc to inline the functions |
| 348 | developers have marked 'inline'. Doing so takes away freedom from gcc to |
| 349 | do what it thinks is best, which is desirable for the gcc 3.x series of |
| 350 | compilers. The gcc 4.x series have a rewritten inlining algorithm and |
| 351 | disabling this option will generate a smaller kernel there. Hopefully |
| 352 | this algorithm is so good that allowing gcc4 to make the decision can |
| 353 | become the default in the future, until then this option is there to |
| 354 | test gcc for this. |
| 355 | |
Paul E. McKenney | a241ec6 | 2005-10-30 15:03:12 -0800 | [diff] [blame] | 356 | config RCU_TORTURE_TEST |
| 357 | tristate "torture tests for RCU" |
| 358 | depends on DEBUG_KERNEL |
| 359 | default n |
| 360 | help |
| 361 | This option provides a kernel module that runs torture tests |
| 362 | on the RCU infrastructure. The kernel module may be built |
| 363 | after the fact on the running kernel to be tested, if desired. |
| 364 | |
| 365 | Say Y here if you want RCU torture tests to start automatically |
| 366 | at boot time (you probably don't). |
| 367 | Say M if you want the RCU torture tests to build as a module. |
| 368 | Say N if you are unsure. |